With respect to overall survival (OS), there were no significant differences between sPD-L1 positive and negative patients at baseline in the GBM (p = 0.56, log-rank test) and WHO grade II–III glioma subgroups (p = 0.68) as well as in confirmed IDH-wt cases (p = 0.63, Supplementary Fig. 2A-C). Here, SPDL1 is linked to glioma.